How do I get rid of this dried crud on the inside of my previously owned tank?

[oddsoxdi]

Hello and thank you for any advice you can offer me.

Day before yesterday I bought a 44 gallon diamond tank - NICE tank!! Unfortunately the previous owner had allowed algae to build up on five of the six sides for what must have been months. The tank has been inactive for three months so this stuff has dried to a really nice cement - most of it scrapes off with a lot of elbow grease and careful use of a razor-scraper. But one side has this purple stuff over most of it and my razor-scraper barely touches it! I don't want to scratch the inside but I want this crap to disappear! Can I use vinegar and newspaper or will that so acidify the tank that it'll become toxic? Is there anything I can safely use to get rid of this nasty crud?


Edited to add: Would you recommend adding new beads of silicon for aquariums in each joint? Thanks for your help.

Diane

 

[Rbishop]

Glass tank I assume...? I would fill with fairly warm water if not hot and add a quart of bleach and let it soak for a day. Then dain and start scraping wih a razor blade, being careful not ti touch the interior silicone bead.

 

[Gill Roy]

"Purple stuff" huh?
Sounds like it was a reef tank in it's previous life and has some coraline on it.
You can use full strength white vinegar on it and not have to fill the tank with it.
To do all 5 panels you would simply turn the side you want to soak downward and use about a pint to soak it for about 20 mins and it should come right off with a soft scrub or some old filter media. Maybe use a towel or something to place over it to keep it all wet for the 20 mins.
Do this on all panels and it shouldn't be a tuff task to complete.